Magnetic refrigeration control system, and method thereof

ABSTRACT

A magnetic refrigeration control system, includes: a first magnetocaloric bed; a pipe, arranged through the first magnetocaloric bed; a coolant, flowing in the pipe; a pump, driving the coolant with a pumping speed; a valve, adjusting a flow period of the flowing coolant; a magnetic module, providing an increasing magnetic field to the first magnetocaloric bed during a magnetization period and providing a decreasing magnetic field to the first magnetocaloric bed during a demagnetization period; and a sensor, detecting a fluid pressure of the coolant flowing in the pipe, the temperature of a refrigerator, and a flowing rate of the coolant flowing in the pipe; and a controller, adjusting the pumping speed, the flow period, the magnetization period, and the demagnetization period according to the temperature, the fluid pressure, and the flowing rate in real time. A magnetic refrigeration control method is also disclosed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosure relates generally to magnetic refrigeration technologies,and more particularly relates to the control of a magnetic refrigerationsystem with better cooling performance.

2. Description of the Related Art

Present refrigeration technology, for example, a refrigerator, afreezer, a room air conditioner, a heat pump and the likes, mainlyemploys a gas compression/expansion cycle. However, a serious problem ofenvironmental pollution is caused by specific Freon gases dischargedinto environment for refrigeration technology based on the gascompression/expansion cycle. Recently, magnetic refrigeration technologyhas been introduced as a highly efficient and environmentally friendlycooling technology. Magnetic refrigeration technology adapts amagnetocaloric effect (MCE) of magnetocaloric materials (MCM) to realizerefrigeration cycles.

Nowadays, the operation frequency of the MCM based magneticrefrigeration system is fixed. For example, the frequency and cycle ofmagnetization or demagnetization to a magnetocaloric material are fixed.But, the cooling environment varies. Thus, for this kind of the magneticrefrigeration system is hard to achieve the best efficiency for variouscooling situations or requirements.

BRIEF SUMMARY OF THE INVENTION

An embodiment of a magnetic refrigeration control system for an outerheat exchanger, includes: a first magnetocaloric bed; a pipe, arrangedthrough the first magnetocaloric bed; a coolant, flowing in the pipe; apump, driving the coolant with a pumping speed; a valve, adjusting aflow period of the coolant flowing in the pipe; a magnetic module,providing an increasing magnetic field to the first magnetocaloric bedduring a magnetization period, and providing a decreasing magnetic fieldto the first magnetocaloric bed during a demagnetization period; asensor, detecting a fluid pressure of the coolant flowing in the pipe,the temperature of the outer heat exchanger, and a flowing rate of thecoolant flowing in the pipe; and a controller, adjusting the pumpingspeed, the flow period, the magnetization period, and thedemagnetization period according to the temperature, the fluid pressure,and the flowing rate.

An embodiment of a magnetic refrigeration control method for cooling anheat exchanger, includes steps of: providing a magnetic refrigerationcontrol system comprising a first magnetocaloric bed; a pipe arrangedthrough the first magnetocaloric bed, and a coolant flowing in the pipe;driving the coolant with a pumping speed; adjusting a flow period of thecoolant flowing in the pipe; providing an increasing magnetic field tothe first magnetocaloric bed during a magnetization period, andproviding a decreasing magnetic field to the first magnetocaloric bedduring a demagnetization period; and detecting a fluid pressure of thecoolant flowing in the pipe, the temperature of the outer heatexchanger, and a flowing rate of the coolant flowing in the pipe;adjusting the pumping speed, the flow period, the magnetization period,and the demagnetization period according to the temperature, the fluidpressure, and the flowing rate, wherein the temperature of the outerheat exchanger is determined by pumping speed, the flow period, themagnetization period and the demagnetization period.

BRIEF DESCRIPTION OF DRAWINGS

The invention will become more fully understood by referring to thefollowing detailed description with reference to the accompanyingdrawings, wherein:

FIG. 1 is a schematic diagram illustrating an embodiment of magneticrefrigeration control system of the disclosure;

FIGS. 2A-2C are schematic diagrams illustrating an embodiment of amagnetic module for proving magnetic field to magnetocaloric beds of themagnetic refrigeration control system shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The making and using of the embodiments of the present invention arediscussed in detail below. It should be appreciated, however, that theembodiments provide many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention.

FIG. 1 is a schematic diagram illustrating an embodiment of magneticrefrigeration control system of the disclosure. The magneticrefrigeration control system 100 comprises at least a controller 110, apump 120, a valve 122, a coolant 124, a pipe 126, a magnetic module 130,a magnetocaloric bed 132, a sensor 140, and an outer heat exchanger 150.The pump 120 and the valve 122 are connected by the pipe 126, and thecoolant 124 flows within the pipe 126. In order to circulate the coolant124, the pipe 126 is constructed as a circulating pipe for example. Thepump 120 drives the coolant 124 to flow, and the valve 122 adjusts theduration period of the flowing of the coolant 124 and the flowing rateof the coolant 124. Also, the pipe 126 is arranged between themagnetocaloric bed 132 and the outer heat exchanger 150. Therefore, themagnetocaloric bed 132 and the outer heat exchanger 150 can exchangeheat with the coolant 124 flowing within the pipe 126.

The magnetocaloric bed 132 contains magnetocaloric materials (MCM). Inan embodiment, when magnetocaloric material is provided with a magneticfield or an increasing magnetic field, magnetocaloric material will heatup. While the magnetic field is held constantly, the coolant 124 isprovided to take away heat generated from the magnetocaloric materials.And once the magnetocaloric material is sufficiently cooled down, themagnetic field is removed or largely decreased. Finally, due to itsnature of having magnetocaloric effect (MCE), the magnetocaloricmaterial cools down. On the other hand, the coolant 124 also takes awayheat from the outer heat exchanger 150 when the magnetocaloric materialcools down. Due to these features, magnetocaloric refrigeration isrealized. The outer heat exchanger here may be heat sink, or similardevices which can exchange heat with the coolant 124 as here describedor other heat exchanging media.

In an embodiment, the operations of the pump 120, the valve 122, and themagnetic module 130 are controlled by the controller 110. For example,the controller 110 can adjust the pumping speed of the pump 120, canopen or close the valve 122, and can adjust the strength or the durationperiod of the magnetic field provided by the magnetic module 130.

It should be noted, the cooling performance and cooling temperaturegradient (the speed of temperature spreading) of magnetocaloricrefrigeration depend on the material characteristics inside themagnetocaloric bed 132, the duration period of the increasing magneticfield provided to the magnetocaloric bed 132, the duration period of thedecreasing magnetic field provided to the magnetocaloric bed 132, thevariation of the magnetic field provided to the magnetocaloric bed 132,the fluid pressure of the coolant 124 in the pipe 126, and the flowingrate of the coolant 124 in the pipe 126, etc. In order to perform bettercooling power or establish the cooling temperature gradient faster, insome embodiments, the sensor 140 detects working and/or environmentfactors such as the fluid pressure of the coolant 124 in the pipe 126,the flowing rate of the coolant 124 in the pipe 126, and the temperatureof the outer heat exchanger 150. And then the controller 110 adjusts thepumping speed of the pump 120, the open duration period of the valve122, the duration period of the increasing magnetic field generated bythe magnetic module 130 and provided to the magnetocaloric bed 132, andthe duration period of the decreasing magnetic field generated by themagnetic module 130 and provided to the magnetocaloric bed 132,according to the parameters, such as the temperature, the fluidpressure, and the flowing rate, obtained by the sensor 140. By feedingback these parameters from the sensor 140 to the controller 110 in realtime, the controller 110 can improve the cooling power or build uptemperature gradient faster. It should be known, that the margin ofadjusting the pumping speed of the pump 120, the open duration period ofthe valve 122, the duration period of the increasing magnetic fieldgenerated by the magnetic module 130 and provided to the magnetocaloricbed 132, and the duration period of the decreasing magnetic fieldgenerated by the magnetic module 130 and provided to the magnetocaloricbed 132, are all dependent on user requirements and designs.

While the magnetic refrigeration control system has been described byway of example and in terms of a brief embodiment, it is to beunderstood that the magnetic refrigeration control system can have notjust one pump, valve, pipe, magnetocaloric bed, outer heat exchanger,and/or magnetic module, however, arrangement of the magneticrefrigeration control system depends described here on requirements ordesigns. Also, the arrangement of the pump, valve, pipe, magnetocaloricbed, outer heat exchanger, and/or magnetic module is not limited to thatdescribed above.

FIG. 2A-2C are schematic diagrams illustrating an embodiment of amagnetic module and magnetocaloric beds for the magnetic refrigerationcontrol system shown in FIG. 1. Refer to FIGS. 1, 2A, 2B, and 2C, themagnetic module 130 comprises a magnet 210 and a driving means 220, andthe driving means 220 is controlled by the controller 110. The axlecenter C of the magnet 210 is connected to the driving means 220. Thus,the driving means 220 drives the magnet 210 to rotate via the powerprovided from the controller 110. The magnet 210 described above may bea permanent magnet, a super conductor based magnet, or a set ofelectro-coils with an outer electrical circuit, and in this embodiment,the magnet 210 is a permanent magnet, but is not to limit thisinvention.

In this embodiment, four magnetocaloric beds 202, 204, 206, and 208 arearranged beside the magnet 210. A vector V represents the direction fromthe axle center C to the magnetic pole P of the magnet 210. When themagnetic pole P rotates to a 0 degree angle, the vector V points to themagnetocaloric bed 202. When the magnetic pole P then rotates to a 90degree angle, the vector V points to the magnetocaloric bed 204. Whenthe magnetic pole P then rotates to a 180 degree angle, the vector Vpoints to the magnetocaloric bed 206. When the magnetic pole P thenrotates to a 270 degree angle, the vector V points to the magnetocaloricbed 208. When the magnetic pole P then further rotates to a 360 degreeangle, the vector V points to the magnetocaloric bed 202 again, i.e. themagnetic pole P rotates for a complete circle and finally back to itsoriginal position where is also at 0 degree. Thus, when the drivingmeans 220 drives the magnetic pole P to rotate from a 0 degree angle to90 degree angle, viewed as aspects of the magnetocaloric beds 202 and204, an increasing magnetic field is provided to the magnetocaloric bed204 by relatively rotating of the magnet 210, and a decreasing magneticfield is provided to the magnetocaloric bed 202 by relatively rotatingof the magnet 210. It should be known, that the driving means 220 candrive the magnetic pole P to rotate from a 90 degree angle back to 0degree angle. Accordingly, viewed as aspects of the magnetocaloric beds202 and 204, a decreasing magnetic field is provided to themagnetocaloric bed 204 by relatively rotating of the magnet 210, and anincreasing magnetic field is provided to the magnetocaloric bed 202 byrelatively rotating of the magnet 210.

Also, different variation rates and/or quantity of the magnetic fieldprovided to the magnetocaloric bed cause different performances andcooling gradients for magnetocaloric refrigeration. Thus, the controller110 can adjust a driving means operation frequency of the driving means220, in order to perform a proper cooling gradient corresponding to userrequirements or designs.

In some embodiments, when rotating the magnetic pole P from a 0 degreeangle to 90 degree angle, the driving means 220 only drives the magneticpole P to rotate to a proper degree of angle larger than a 45 degreeangle (such as 45.1, 46, or 50 degrees, . . . etc), as shown in FIG. 2B.When the magnetic pole P reaches a determined degree angle, the drivingmeans 220 stops driving the magnet 210 from rotating, namely thecontroller 110 stops providing the power or reducing the power to thedriving means 220 at this time. Due to the magnetocaloric beds 202, 204,206, and 208 containing of magnetocaloric materials which is basicallymagnetic contractive, and wherein the distance between the magnetic poleP and the magnetocaloric bed 204 is less than the distance between themagnetic pole P and the magnetocaloric bed 202, the magnetic pole P willrotate to a 90 degree angle automatically by the magnetic attractionforce between the magnetic pole P and the magnetocaloric bed 204, asshown in FIG. 2C. When the magnet 210 requires rotating, or a decreasingmagnetic field is required to be provided to the magnetocaloric bed 204,the driving means 220 will start to drive the magnet 210 to rotate. Dueto the magnet 210 rotates automatically such that the driving means 220not being required to be provided power all the time, the totalconsumption of power can be further reduced.

Those who are skilled in this technology field can delete, add, orchange the arrangement of the magnetocaloric bed, magnet, and/or drivingmeans described above without departing from the scope and spirit ofthis invention. For example, there can be eight magnetocaloric beds inthe magnetic refrigeration control system, and the magnetocaloric bedsmay be arranged in a circular path with the axle center C as a center,wherein the eight magnetocaloric beds are disposed at 0, 45, 90, 135,180, 225, 270, and 315 degree angles respectively. Thus, when rotatingthe magnetic pole P from a 0 degree angle to 45 degree angle, thedriving means 220 can drive the magnetic pole P to rotate to a degreeangle just larger than a 22.5 degree angle.

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. Those who are skilled in this technology can still makevarious alterations and modifications without departing from the scopeand spirit of this invention. Therefore, the scope of the presentinvention shall be defined and protected by the following claims andtheir equivalents.

What is claimed is:
 1. A magnetic refrigeration control system forcooling an outer heat exchanger, comprising: a first magnetocaloric bed;a pipe arranged through the first magnetocaloric bed; a coolant flowingin the pipe; a pump, driving the coolant with a pumping speed; a valve,adjusting a flow period of the coolant flowing in the pipe; a magneticmodule, providing an increasing magnetic field to the firstmagnetocaloric bed during a magnetization period, and providing adecreasing magnetic field to the first magnetocaloric bed during ademagnetization period; a sensor, detecting a fluid pressure of thecoolant flowing in the pipe, the temperature of the outer heatexchanger, and a flowing rate of the coolant flowing in the pipe; and acontroller, adjusting the flow period, the pumping speed, themagnetization period, and the demagnetization period according to thetemperature, the fluid pressure, and the flowing rate in real time. 2.The magnetic refrigeration control system of claim 1, wherein themagnetic module has a magnet and a driving means controlled by thecontroller, wherein the driving means shifts the magnet towards thefirst magnetocaloric bed for providing the increasing magnetic field tothe first magnetocaloric bed, and the driving means shifts the magnetaway from the first magnetocaloric bed for providing the decreasingmagnetic field to the first magnetocaloric bed.
 3. The magneticrefrigeration control system of claim 2, further comprising a secondmagnetocaloric bed, wherein the controller provides a power to thedriving means, the driving means shifts the magnet to a positionaccording to the power, and the distance between the firstmagnetocaloric bed and the position is larger than the distance betweenthe second magnetocaloric bed and the position, and the controller cutsoff or reduces the power providing to the driving means when the magnetreaches to the position.
 4. The magnetic refrigeration control system ofclaim 3, wherein the first magnetocaloric bed and the secondmagnetocaloric bed contain magnetocaloric materials, the magnetocaloricmaterials are heated up when the increasing magnetic field is provided,and the magnetocaloric materials are cooled down when the decreasingmagnetic field is provided.
 5. The magnetic refrigeration control systemof claim 2, wherein a driving means operation frequency of the drivingmeans is determined by the controller according to the temperature, thefluid pressure, and the flowing rate.
 6. A magnetic refrigerationcontrol method for cooling an outer heat exchanger, comprising steps of:providing a magnetic refrigeration control system comprising a firstmagnetocaloric bed, a pipe arranged through the first magnetocaloricbed, and a coolant flowing in the pipe; driving the coolant with apumping speed; adjusting a flow period of the coolant flowing in thepipe; providing an increasing magnetic field to the first magnetocaloricbed during a magnetization period, and providing a decreasing magneticfield to the first magnetocaloric bed during a demagnetization period;detecting a fluid pressure of the coolant flowing in the pipe, thetemperature of the outer heat exchanger, and a flowing rate of thecoolant flowing in the pipe; and adjusting the pumping speed, the flowperiod, the magnetization period, and the demagnetization periodaccording to the temperature, the fluid pressure, and the flowing ratein real time, wherein the temperature of the outer heat exchanger isdetermined by the pumping speed, the flow period, the magnetizationperiod and the demagnetization period.
 7. The magnetic refrigerationcontrol method of claim 6, further comprising: shifting a magnet towardsthe first magnetocaloric bed for providing the increasing magneticfield; and shifting the magnet away from the first magnetocaloric bedfor providing the decreasing magnetic field.
 8. The method of claim 7,further comprising: shifting the magnet to a position by providing apower to a driving means, wherein the distance between the position andthe first magnetocaloric bed is larger than the distance between theposition and a second magnetocaloric bed; and cutting off or reducingthe power providing to the driving means when the magnet reaches to theposition.
 9. The method of claim 8, wherein a driving means operationfrequency of the driving means is determined according to thetemperature, the fluid pressure, and the flowing rate.